Do not click that link. I am a consultant for WashingtonPost.com and fully empowered to demand that no one here follow that link. Not sure if you should believe me? Why take the chance?
I've gotten so much stuff removed from the internet without even touching the DMCA, it's kind of sad actually
And this company is actually registered? Or it's all fake?
The company being registered doesn't matter, I don't expect people to search through 250+ jurisdictions around the world to figure out where its registered. So you can pretend the company name is the same as the domain name, reference "Your Client" in the sternly worded email, and "trade secrets" or "unauthorized privileged information" being hosted on "your server"
A lot of companies will take it down very quickly and apologize profusely. Anywhere in the world, US, Russia, you name it.